In the pharmaceutical industry, material such as powder is often transported in containers for a variety of reasons, including for example to patients in clinical trials or to formulators for development. Accurate and rapid filling of powders into containers would, therefore, provide improvements such as in clinical trial management and formulation development, by increasing efficiency and reducing costs.
Under current practice, both manual and automated methods exist for delivering material, for example powder, into containers, although such methods suffer from drawbacks. For example, the accuracy of the method can be influenced by such factors as the nature of the material, including the flow and density of powder, environmental conditions under which the operation takes place (e.g. humidity and temperature), and other factors.
In addition, manual methods can be laborious, time consuming, potentially inaccurate due to human error, etc., and therefore are useful only for very low-throughput applications. In such methods, for example, individual doses of powder may be weighed out by an individual using a balance and then transferred into a container. Alternatively, the powder may not be weighed directly but rather may be transferred into a container situated on a balance, at which time the weighing step occurs. These methods are neither time- nor cost-effective, particularly when a higher-throughput operation is needed.
Low-throughput automated methods for filling containers with powders, which may avoid some of the problems associated with manual methods described above, typically employ one of two mechanisms: those with gravity feed mechanisms like the Symyx Autodose POWDERNIUM®, or those with auger mechanisms like the Bohdan FLEXIWEIGH®. Although such systems are generally accurate and flexible for both powder amount and type, they are still relatively slow, often requiring two to five minutes of delivery time per dose. Thus, those methods are practical primarily for low-throughput applications, such as laboratory work or formulation work including, for example, when 10-30 containers filled per hour is sufficient.
There are high-speed automated machines for high-throughput delivery of powders into, for example, capsules and other containers. One such method can fill many thousands of capsules or containers per hour and employs a dosator-type method. The dosator-type method involves plunging a cylinder of specific volume into a powder supply, or use of a vacuum to pick up powder in a cylinder of specific volume. The powder is then densified to form a cohesive plug. The powder plug is then ejected or released into a container or capsule. A disadvantage associated with this method may include, for example, the limitatibon on the type of powders which can be used, such as, for example, those which have the ability to form plugs by this method. Another disadvantage of the dosator-type method may include the potential loss of a large amount of powder due to either the necessary height of the powder supply, which must be higher than the height of the cylinder, or the loss of powder in vacuum systems where static charges may lead to inconsistent weight fills.
As another example of an automated high-throughput powder dispensing method, a method currently used for filling capsules uses a tamping-type mechanism which involves filling chambers in a dosating disk with powder which is then compressed with tamping pins to form plugs, then releasing the plugs into the capsules through an ejection hole in the dosating disk.
There are advantages of the tamping-type method relative to the dosator-type method. The tamping-type method accommodates a greater variety of powder types than the dosator-type method, and results in less powder loss during processing. The tamping-type mechanism is also often simpler, with fewer moving parts and no vacuum or gas required to hold or release the powder doses.
There is thus a need for improved methods and apparatuses for delivering powders into containers. A need exists for a method and apparatus which can be used to accommodate a variety of powder types and deliver the powder into the container in a fast and efficient manner.
Although the present invention may obviate one or more of the above-mentioned disadvantages, it should be understood that some aspects of the invention might not necessarily obviate one or more of those disadvantages.
In the following description, various aspects and embodiments will become evident. In its broadest sense, the invention could be practiced without having one or more features of these aspects and embodiments. Further, these aspects and embodiments are exemplary. Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practicing of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.